Specific Types of Cancer Linked to Short Sleep Duration

With that being said, few studies have investigated the link between sleep duration and risks for cancers other than breast cancer.

A 2016 study set out to determine the link between sleep duration and incidences of 18 specific cancers using data from the NIH-AARP Diet and Health Study. The study included data from 297,185 adults between 50 and 71 years of age. Fifty-eight percent of the cohort were men and 42 percent were women.

Sleep duration was self reported and categorized into the following groups:

Fewer than five hours

Between five and six hours

Between seven and eight hours

Nine hours or more

Cancers linked with short sleep duration in men

Researchers found a significant increase in stomach cancer risk in men who got between five and six hours of sleep compared to those who slept for between seven and eight hours.

The study also revealed a suggested link between the following cancers and a sleep duration of less than five hours:

Head and neck cancer

Myeloma (a cancer of plasma cells)

For men who slept for between five and six hours, a suggested link was made with the following cancers:

Bladder cancer

Non-Hodgkin lymphoma

Is short sleep duration beneficial for women?

Interestingly, the study data suggested that women who slept for less than five hours appeared to be less likely to develop breast cancer.

Study data also suggested that women who slept for nine hours or more had a reduced risk for ovarian cancer, but an increased risk for Non-Hodgkin lymphoma.

A few caveats

It's important to note that the link between stomach cancer in men who got between five and six hours of sleep was the only association that reached statistical significance. All other associations were suggested, but did not reach the threshold for statistical significance.

Perhaps most surprising in this research was its suggestion that women who slept for less than five hours were less likely to develop breast cancer.

So, why did this study find a suggested link between short sleep duration and reduced breast cancer risk? The authors suggest this could be due to their data being obtained from older women — estrogen levels are considered to be a risk factor for breast cancer and short sleep durations may be a symptom of low estrogen in post-menopausal women.

Do other factors or conditions influence risk?

This study adjusted for all cancer risk factors for which it had data. These factors included:

It's worth nothing that both excessively short sleep durations and excessively long sleep durations may be caused by an underlying health condition, which could influence cancer risk.

Conclusion

There does appear to be a link between sleep health and cancer risk. However, studies report mixed results when it comes to the risk for specific cancers and whether other health conditions or lifestyle factors may influence that risk.

The best thing you can do is recognize the importance of sleep and take steps to improve your sleep if you feel you're not getting enough or if you find that you are regularly sleeping for an excessive amount of time.

Start by talking with your doctor or other health professional about any concerns you may have.

Martin is the creator of Insomnia Land’s free insomnia sleep training. His online course uses CBT techniques to teach participants how to sleep without relying on sleeping pills. More than 4,000 insomniacs have completed his course and 97 percent of graduates say they would recommend it to a friend.

Martin is the creator of Insomnia Coach, an eight-week course that combines online sleep education with individual sleep coaching. His course helps clients improve their sleep so they can enjoy a better life with more energy and start each day feeling happy, healthy, rested, and refreshed. Martin also runs a free sleep training course that has helped over 5,000 insomniacs. He holds a master’s degree in health and wellness education and studied clinical sleep health at the University of Delaware.